Instrument for projection-drawing



(No Model.)

J. M. SILLIMAN. INSTRUMENT POE PROJECTION DRAWING,

No. 262,137. Patented Aug. 1; 1882.

WITNESSES INVENTOR VZZUM/Z y B f ATTORNEYS.

UNITED STATES PATENT @rrrcn.

JUSTUS M. SILLIMAN, 'OF EASTON, PENNSYLVANIA.

INSTRUMENT FOR PROJECTION-DRAWING.

SPECIFICATION forming part of Letters Patent No. 262,137, dated August1, 1882.

(N model.)

ing a weight or tension-spring at its lower end 4 is wound in theinverse direction of the wires of the drawing-frame, whereby the wiresof the drawing-frame will always be held taut, and will always bring thethe upper and lower edges of the drawing-frame parallel with the shaft.

The invention further consists in a drawingframe provided with pivotedgraduated arms, with quadrants, and with graduated triangular frames formaking crystallographic drawings, as will be set forth hereinafter.

Reference is to be had to the accompanying drawings, forming a part ofthis specification, in which similar letters of reference indicatecorresponding parts in both the figures.

Figure l is a plan view of my improved instrument forprojection-drawing, showing it attached on a drawing-board. Fig. 2 isacrosssectional elevation of the instrument and the board on the line w00, Fig. 1.

A quadrilateral frame, A, made of wood or metal, and adapted to restflat upon a drawingboard, B, is provided with graduations or scales andpivoted arms, as will be fully described hereinafter.

To the frame A two wires, cords, or equivalents, O, are attached bymeans of bindingscrews D, or equivalent devices, which wires each passthrough an apertured guide-block, E, projecting upward above the topsurface of the board at the upper edge of this board, which blocks E arepreferably attached to and project from a bar, F, resting against theupper edge of the board and connecting two arms, G, clamped on the boardB by screws to, and projecting from the upper edge of the board at rightangles to this edge, as shown.

A roller, H, or a pulley-shaft or equivalent is journaled in the outerends of the arms G, and to this roller the wires or cords O are fast.-ened in such a manner as to wind on the roller (or pulleys) when theframe Ais moved toward the upper edge of the board B.

A cord or wire, J, is attached to and wound on the shaft or roller H ator near the middle of the same, and has a weight, K, or equivalentdevice attached to its lower free end, this cord or wire J being woundon the roller or shaft H in the inverse direction of the windings of thecords or wires 0, so that when the wires 0 are wound on this shaft orroller H the cord or wire J will be unwound.

The blocks E are provided with apertures, which are beveled upward fromthe outer to ward the inner surfaces of the blocks E on a quadrant-line,as is shown in dotted lines, so that when the frame A is moved sidewisethe wires 0 will not be kinked by-the edges ofthe apertures in theblocks E. These blocks are provided with apertures increasing in acurved line from the outer toward the inner surface.

The frame A is provided with graduated scales at the top and bottomedges, and has two quadrant-shaped recesses, L, the rounded edges ofwhich are divided into degrees. The middle transverse strip, M, of theframe A is provided with a different scale on each edge. Arms N,provided with graduated scales along the edges, are pivoted to the lowerpart of the frame A, so as to swing in the quadrant-recesses L, theouter ends of these arms resting on a projection, I), along the curvededge of the recess, as shown. At the outer or free ends these arms N areprovided with bindingscrews 0, for locking them in position at anydesired angle to the lower edge of the frame A. Arms 1? P are pivoted tothe upper corners ot' the frame A, and these arms are pro vided at theirpivoted ends and at their inner edges with semicircular projections Q Q,having the semicircular edge subdivided into degrees. The arms P areprovided with graduated scales on the outer edges, and can be held atany desired inclination by means of binding-screws R, acting on therounded edges of the projections Q Q, as shown. The upper part of theframe A is provided with edges S and T, having the directions of theprojected axes in the rectangular and hexagonal systems too inggraduated in accordance with the lengths of the projections of equalaxes.

The operation is as follows: The wiresC are so adjusted that they willbe taut when the Iongitudinal edges of the frameAare parallel with theedges of the board B and with the shaft or roller H. If the frame A ismoved toward the upper edge of the board B, the wires (J will be woundupon the roller H by the action of the weight K on the cord or wire J,for by this movement of the frame A the wires 0 O are slackened, and theweight, drawing downward, necessarily causes a rotation of the roller H,whereby the wiresC will be wound on the roller. The same length of eachwire 0 is wound on the roller, for both ends of the roller rotate withthe same rapidity, and consequently the two ends of the frame A willmove with the same rapidity, and in all positions the straight upper andlower edges of the frame A will be parallel with the corresponding edgesof the board B. If the frame A is moved toward the lower edge of theboard B, the wires 0 will be unwound from the roller H, and the wire orcord J will be wound on the roller. It the frame A is moved sidewise,the wires 0 U will bend at the blocks E. In whatever direction the frameA has been moved, it can always be placed parallel with the edges of theboard B by pulling the wires O taut-that is to say, there must not beany slack in either wire. Parallel and rectangular lines can thus bedrawn very easily on the board by drawing the pen or pencil along thelongitudinal edges or ends of the frame A, and lines of any desiredinclination can be drawn by drawing the pen or pencil along the arms N Nand P P, which can be inclined as desired and locked in position.

The arms I? P will be found to be of special service in constructing theoutlines of shadows.

The triangle S is to be used for making crystallographic drawings of allthe systems but the hexagonal, and the frame T is to be used for makingcrystallographic drawings of the hexagonal system.

By the use of this instrument all isometrical drawings and cabinet andcrystallographic projections can be very easily drawn to any desiredscale. It is also designed for the construction of stress diagrams ingraphical statics. If one of the movable arms is adjusted in thedirection of a represented ray of light and the other three arms areadjusted in directions of projections of rays on the three coordinateplanes, the outline of the shadows in isometrical drawing and cabinetprojections can be rapidly constructed.

Having thus described my invention, Iclaim as new and desire to secureby Letters Patent 1. The combination, with the drawing-frame A, of thewires 0, the roller or shaft H on which these wires are wound, the wireJ,wound on the roller or shaft H in the inverse direc tion of the wires0, and of the weight K, attached to the lower end of the wire J,substantially as herein shown and described.

2. The combination, with the drawing-frame A, of the wires 0, theguide-blocks E, the shaft or roller 11, the wire J, and the weight K,substantially as herein shown and described, and for the purpose setforth.

3. The combination,with the drawing frame A, of the wires 0, theguide-blocks E, provided with apertures increasing in size on a curvedline from the outer toward the inner surface, the wire J, and the weightK, substantially as herein shown and described, and for the purpose setforth.

4. The combination, with the drawing-board B, of the drawing-frame A,the arms G G, the guide-blocks E, the roller H, the wires 0 and J, andthe weight K, substantially as herein shown and described, and for thepurpose set forth.

5. The combination, with the drawing-fra|ne A, of one or more trianglesprojecting from its upper edge, which triangles have their legs orshanks inclined differently and provided with difl'ereut-graduatedscales, whereby crystallographic drawings can be made, substantially asherein shown and described, and for the purpose set forth.

JUSTUS MITCHELL SILLIMAN.

Witnesses OSCAR F. GUNZ, (J. SEDGWlOK.

